Methane emissions from rice cultivation:

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1 Methane emissions from rice cultivation: IRRI s mitigation options Ma. Carmelita Alberto and Reiner Wassmann Rice & Climate Change Crop & Environmental Sciences Division International Rice Research Institute 6 November 2015

2 Outline of Presentation Significance of CH4 emissions on Climate Change CH4 emissions from rice cultivation Mitigation strategies

3 There are many uncertainties about the future climate, BUT two universal trends are predicted by most climate change models: (1) Temperatures will increase more heat stress Sea level rise (thermal expansion of water and melting of ice) (Source: EPA website) (2) More frequent and severe climate extremes more floods more droughts

4 Climate Change will Aggravate the Abiotic Stresses in Rice! (1) Heat stress daytime What would be the impacts of Climate Change on rice? nighttime extreme heat episodes can irreversibly damage rice yield, grain quality, germination and fertilization heat stress during flowering complete sterility heat stress during ripening reduced grain filling & poor milling quality (more broken grains) Hotspots of heat stress on rice and frequency of occurrence ( ) Due to climate change, the number of hot days and warm nights have increased higher nighttime temp reduced yields by as much as 10% for every 1 C increase in minimum temp due to increase in respiration (Peng et al., 2004)

5 Climate Change will Aggravate the Abiotic Stresses in Rice! (2) Drought or water stress most widespread and damaging of all abiotic stresses major source of yield & economic loss in rice production affects all stages of rice growth and development the strong effects of drought on grain yield are largely due to the reduction of spikelet fertility and panicle exsertion With the onset of climate change, the intensity and frequency of droughts are predicted to increase in rainfed rice-growing areas and droughts could extend further into water-short irrigated areas

6 Climate Change will Aggravate the Abiotic Stresses in Rice! (3) Salinity NaCl major salt that causes this problem rice is highly sensitive to salt stress in its early growth stage and a few days before panicle initiation to flowering stage ECe 3 ds/m salinity threshold for rice When sea level rises due to climate change, saline water will be brought inland and expose more rice growing areas in the low-lying deltas and coastal areas to salty conditions

7 Climate Change will Aggravate the Abiotic Stresses in Rice! (4) Submergence/ Submergence/ Flooding Mega deltas in Asia are most vulnerable Submergence either short-term (flash floods) or long-term (stagnant flooding) can affect rice crops at any stage of growth The chances of survival are extremely low when completely submerged during the crop s vegetative stage With climate change, major flooding events are likely to increase in frequency caused by sea level rise in coastal areas and the predicted increased intensity of tropical storms

8 Contribution of rice production to greenhouse gas effect Nitrous oxide (N2O) Inorganic fertilizers 25X 300X

9 Why is methane important? radiative forcing: CO2 (~60%), CH4 (~20%) (Forster et al., 2007) CH4 GWP: 25 (100-yr time horizon) (Forster et al., 2007) CH4 concentration: 0.7 to 1.80 ppm V (Hartmann et al., 2013) total global CH4 budget: Tg CH4 yr-1 (Dlugokencky et al., 2011) Residence time: CH4 (~9 yrs), CO2 (~100 yrs), N2O (~170 yrs) Because CH4 is both a powerful GHG and short-lived compared to CO2, achieving significant reductions would have a rapid and significant effect on atmospheric warming potential.

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11 Outline of Presentation Significance of CH4 emissions on Climate Change CH4 emissions from rice cultivation Mitigation strategies

12 Baseline Methane Research (funded by US-EPA, ) Irrigated Rainfed Deepwater Interregional Program on Methane Emissions from Rice Fields (funded by UNDP/GEF, )

13 Rice ecosystems in Asia Rainfed lowland Irrigated CH4 emissions from different rice fields: irrigated rice continuously flooded rice > flood prone rainfed rice deepwater rice > drought prone rainfed rice > tidal rice Rainfed upland Deepwater

14 Methane emissions from rice paddy (FAOSTAT, 2015) About 75% of our global rice production comes from irrigated rice-based cropping systems

15 Increasing Human Population Rice is the staple food of more than 50% of the world s population 90% of world s rice is grown and consumed in Asia (UN, 2015)

16 Methane in paddy fields Flooding creates anaerobic condition Pools entrapped CH4, dissolved CH4 in soil solution Pools: Fluxes: plant-mediated, ebullition, diffusion Fluxes

17 Factors affecting CH4 emissions in paddy fields Flooding (Eh < -150 mv) Organic substrate ( straw residues, green manure, animal manure) Soil type (heavy clay soils) Soil temperature (35 C) Soil ph 6.4 to 7.8 Tillage Rice cultivar Fertilizers containing nitrates and sulfates inhibit CH4 production

18 Outline of Presentation Significance of CH4 emissions on Climate Change CH4 emissions from rice cultivation Mitigation strategies

19 water-saving practices mid-season drainage intermittent irrigation safe alternate wetting and drying (AWD) efficient nutrient management smart management of rice residues

20 Safe alternate wetting and drying (AWD) Start AWD at 10 DAT with 5-cm floodwater Irrigate when water is 15-cm below soil surface Keep 5-cm floodwater at flowering (one week before and one week after) Save water: 15-30% less irrigation water Maintain yield: No yield penalty Increase water productivity Increase profit in deep well and shallow tube well systems Message for farmers: Water is there even when you can t see it

21 AWD reduces GWP contribution of N2O and CH4 AWD decreased CH4 emissions by 60 90% during the DS compared with continuous flooding (CF) (Hosen et al., 2010) N topdressing immediately before or after irrigation (AWD 2) decreased N2O emissions by 80% compared with N topdressing 2 days before irrigation (AWD 1) When the field was kept flooded for a week after N topdressing (AWD 3), N2O emission decreased similar to CF

22 Promoting AWD IRRI has been promoting AWD as a smart water-saving method that reduces GHG Through the national emissions from irrigated rice agricultural research and extension systems (NARES), farmers are being trained and the use of AWD are being promoted in Bangladesh, the Philippines, and Vietnam

23 AWD is part of the Palay Check System (Philippines)

24 AWD Propagation in Vietnam Decision Farmers use/apply AWD irrigation AWDshould is directly mentioned as one technology to not only greatly save water mitigation option by the Ministry of consumption and reduce GHGs emissions in Agriculture Vietnam irrigated rice fields, butof also increase rice productivity.

25 CCAC Paddy Rice Component: Implementing Partners: IRRI in Asia and CIAT in Latin America (with support from CCAFS) First-Mover Countries (Partner Countries for Implementation): Viet Nam Bangladesh Colombia Goal: To disseminate alternate wetting and drying (AWD) on large scale to facilitate both, more stable food supply and reduction in methane emissions.

26 Efficient Nutrient Management Rice Crop Manager is a computer and mobile phone-based application provides farmers with site- and season-specific recommendations for fertilization allows farmers to adjust nutrient application to crop needs in a given location and season

27 Smart management of rice straw residues Shallow tillage of residues immediately after harvest Partial aerobic decomposition of residues under dry fallow condition

28 Impact of straw incorporation & water management during fallow and growing periods on reduction in CH4 emissions Reference Year/Season Wassmann et al., WS 1993 DS 1993 WS 2013 WS 2014 DS 2014 WS 2013 DS 2015 DS Alberto et al., 2015 Alberto et al., 2015 Straw Residue incorporated Fallow period Flooded Growing period % CH4 reduction Flooded CH4 emission (kg CH4 ha-1) 193 ± 41 incorporated Dry Flooded 106 ± incorporated Dry Intermittent AWD 53 ± (reference)

29 Smart management of rice straw residues Shallow tillage of residues immediately after harvest Partial aerobic decomposition of residues under dry fallow condition Use biochar instead of fresh rice straw

30 Innovative handling and uses of rice straw and rice husks

31 Key Messages (Richards and Sander, 2014) Flooded rice produces approximately Mt of CH4 per year, or about 10-12% of the anthropogenic emissions from the agriculture sector globally. Alternate wetting and drying (AWD) is a rice management practice that reduces water use by up to 30% and can save farmers money on irrigation and pumping costs. AWD reduces methane emissions by 48% without reducing yield. Efficient nitrogen use and application of organic inputs to dry soil can further reduce methane emissions

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33 Two approaches Mitigation: develop new technologies that can reduce greenhouse gas emissions and increase the C sequestration in biomass and soil (reduce the C footprint) Adaptation: development of rice plants and crop management to withstand extreme climate and to make rice-cropping systems more resilient

34 developing climate-proof rice varieties crop diversification crop intensification decision support systems

35 Making rice climateclimate-proof drought submergence salinity heat

36 Shifting from traditional rice cultivation to crop diversification and intensification Block UY Rice Rice 7 t/ha 4.5 t/ha Block UE Dry seeded rice Rice Mungbean 6 t/ha 4.5 t/ha 1.2 t/ha Block UJ Maize Dry seeded rice 11 t/ha D J F M A Rice 5 t/ha M J J A S 4.5 t/ha O N D

37 WeRise (weather-rice-nutrient integrated decision support system) Weather advisory Grain yield advisory WeRise provides complimentary information to existing systems WeRise can describe the characteristics of upcoming rainy season (start/end of season, distribution of rainfall, flood/drought occurrences) and can predict GY of farmers preferred varieties as a function of sowing date, timing of appropriate fertilizer application at crucial crop growth stages Available information from WeRise Flood 1 in 5 years Weather prediction (10days) GY prediction at different sowing dates Cropping calendar Optimal fertilizer application timings Drought 1 in 5 years Predicted 10 days rainfall On-site evaluation (Weather) Rainfall 7 Temp max Vapor pressure WeRise prediction 6 GY(kg ha-1) Temp min On-site evaluation (GY) 5 + WeRise Field testing 4 Farmers practice 3 Variety: IR64 Location: C Java 2 1 Observed WeRise Prediction Oct 6 Oct 9 Oct 12 Oct 15 Oct 18 Oct 21 Oct 24 Oct 27 Oct 30 Nov 2 Nov 5 Nov 8 Nov 11 Nov 14 Nov 17 Nov 20 Nov 23 Nov 26 Nov 29 Dec 2 Dec 5 Dec 8 Dec 11 Dec 14 Dec 17 Dec 20 Dec 23 0 Sowing date

38 Operation of Mobile Phone App Obtain site-specific information from farmer/ operator Cloud based server Provide management recommendation Rice Crop Manager Nutrients Weeds Irrigation. New Modules GHG emission calculator Climate-adjusted yield targets Climate-Informed Rice Crop and Low Emission Manager => CIRCLE Manager

39 Thank you

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